PPT 14: Cardiac Arrhythmias Flashcards
Exam 2 (55 cards)
How prevalent are cardiac arrhythmias in anesthetized patients?
50%
What are the types of cardiac arrhythmias?
- Bradycardia - Slowing (<60 bpm)
- Block
- Tachycardia
- Supraventricular (SVT, atrial)
- Sinus (regular)
- Ventricular Tachycardia (Vtach) - Fibrillation (Atrial or Ventricular)
What are the components of the intrinsic conduction system of the heart?
Sinoatrial node/pacemaker
Atrioventricular node
Atrioventricular bundle/bundle of His
Purkinje fibers
Which part of the intrinsic conduction system is the pacemaker of the heart? What is the contraction rate?
SA node - 75 beats/min
The _______ is the crescent shaped node in right atrium of the intrinsic conduction system
Sinoatrial node/pacemaker
The _______ is the junction of atria and ventricles of the intrinsic conduction system
Atrioventricular node
How fast does the AV node contract?
40-50 beats/min - slow
The _______ is in the interventricular septum of the intrinsic conduction system
Atrioventricular bundle/bundle of His
The _______ is spread within the muscle of the ventricle walls of the intrinsic conduction system
Purkinje fibers
Discuss the changes of the electrocardiogram throughout the intrinsic conduction system
Impulses that deviate from the normal electrical pathway are _______
Arrhythmias
What are the different types of abnormalities of arrhythmias?
- Site of origin
- Rate
- Regularity
- Conduction
What are the 3 main ions that determine cardiac action potential?
- Sodium
- Potassium
- Calcium
Discuss the phases of ion channel currents in cardiac action potential
Discuss the three states of sodium channels
- Resting
- slowly approaching threshold
- m gates closed - Activated
- threshold reached; m gates open
- massive sodium influx - Inactivated - h gates close
The ________ is the time between the inactivation and resting states of sodium channels
Refractory period
K+ channels are open at rest are called ______
Inward rectifier channels - Very little flow (electrical gradient)
______ establish the membrane potential of resting cardiac cell
K+ current
Ca++ channels open _____ and at more ______ potentials
slowly and positive
What are the 2 main classes of arrhythmias?
- Disturbances in Impulse Formation
- Disturbances in Impulse Conduction
What are the types of disturbances in impulse formation that result in arrhythmias?
- Early or late afterdepolarizations
- SA/AV nodal abnormalities
- Ion changes
- SNS stimulation
What are the types of disturbances in impulse conduction that result in arrhythmias?
- Block
- Reentry
Abnormal depolarizations that occur during phase 2, 3, or 4
Afterdepolarizations (AD)
Differentiate between Early (EAD) and Delayed Afterdepolarizations (DAD)
Early Afterdepolarizations (EAD)
- Phase 2 or 3
- Sodium or calcium channels
Delayed Afterpolarizations (DAD)
- Occur before a normal action potential
- Elevated intercellular calcium
